The PCN working group of the Internet Engineering Task Force IETF is investigating pre-congestion notification mechanisms to implement traffic control as for instance admission control and flow termination procedures (see for instance the IETF draft draft-ietf-pcn-architecture-08). The packet marking layer of the architecture includes a mechanism by which PCN interior nodes monitor traffic rates on their links and mark packets depending on the type of pre-congestion. An admissible rate (AR) and a supportable rate (SR) need to be defined for each link (L).
The AR-pre-congestion mechanism results in the admission control function not allowing new flows, while the SR-pre-congestion mechanism can result additionally in the termination function to terminate some previously admitted flows (see for instance FIG. 1).
The filling level of the network, which supports a maximum number of flows, without degrading their QOS, obviously depends on the setting of the specific values of AR and SR for the different links.
The values of AR and SR have to be configured for all PCN interior nodes, and are crucial for the overall operation of the network. The exact values of AR and SR have to be defined by the network operator and can possibly be different for different links within the network.
There exist a need for improved traffic management methods and associated devices.